We are building a web application where we can embed multiple tableau dashboards from tableau server through Javascript API. But, while we re-use trusted ticket to embed multiple dashboards, we can able to visualize a first dashboard. for subsequent URL's with same trusted ticket, we wouldn't be able to embed. Kindly help me on this?

Once a trusted ticket is redeemed, it has served its purpose and cannot be used again to load a new view directly. Your code will need to generate separate tickets for each view. Alternatively, here's an older blog post where Russel Christopher described "unrestricted" tickets (I have not used these, however, so I can't advise on whether they're a good idea in your case):

The first time you redeem a trusted ticket, the server will set a cookie in the browser. After that, you can then access views using their normal url. The only "tricky" part is that you'll need to wait for the ticket to be redeemed before you can access the other views.

SO one question over here Do we need to use different tickets for each view or a single token can be used by all the view and we need to wait for the ticket to be redeemed before we can access the other view.